[PATCH] cmd: move ELF load and boot to lib/elf.c
Maxim M. Moskalets
maximmosk4 at gmail.com
Fri Apr 26 17:31:31 CEST 2024
On 26.04.2024 17:32, Heinrich Schuchardt wrote:
> On 26.04.24 11:11, Maxim Moskalets wrote:
>> Loading and running the ELF image is the responsibility of the
>> library and should not be associated with the command line interface.
>>
>> It is also required to run ELF images from FIT with the bootm command
>> so as not to depend on the command line interface.
>>
>> Signed-off-by: Maxim Moskalets <maximmosk4 at gmail.com>
>> ---
>> cmd/elf.c | 49 +++++++++++++++++--------------------------------
>> include/elf.h | 10 ++++++++++
>> lib/elf.c | 36 ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 63 insertions(+), 32 deletions(-)
>>
>> diff --git a/cmd/elf.c b/cmd/elf.c
>> index df4354d374..8bbdc67db7 100644
>> --- a/cmd/elf.c
>> +++ b/cmd/elf.c
>> @@ -20,21 +20,6 @@
>> #include <linux/linkage.h>
>> #endif
>>
>> -/* Allow ports to override the default behavior */
>> -static unsigned long do_bootelf_exec(ulong (*entry)(int, char *
>> const[]),
>> - int argc, char *const argv[])
>> -{
>> - unsigned long ret;
>> -
>> - /*
>> - * pass address parameter as argv[0] (aka command name),
>> - * and all remaining args
>> - */
>> - ret = entry(argc, argv);
>> -
>> - return ret;
>> -}
>> -
>> /* Interpreter command to boot an arbitrary ELF image from memory */
>> int do_bootelf(struct cmd_tbl *cmdtp, int flag, int argc, char
>> *const argv[])
>> {
>> @@ -44,8 +29,8 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag, int
>> argc, char *const argv[])
>> #endif
>> unsigned long addr; /* Address of the ELF image */
>> unsigned long rc; /* Return value from user code */
>> - char *sload = NULL;
>> int rcode = 0;
>> + Bootelf_flags flags = {0};
>>
>> /* Consume 'bootelf' */
>> argc--; argv++;
>> @@ -53,7 +38,10 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag,
>> int argc, char *const argv[])
>> /* Check for [-p|-s] flag. */
>> if (argc >= 1 && (argv[0][0] == '-' && \
>> (argv[0][1] == 'p' || argv[0][1] == 's'))) {
>> - sload = argv[0];
>> + if (argv[0][1] == 'p')
>> + flags.phdr = 1;
>> + printf("## Try to elf hdr format %s\n",
>> + flags.phdr ? "phdr" : "shdr");
>> /* Consume flag. */
>> argc--; argv++;
>> }
>> @@ -76,14 +64,6 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag,
>> int argc, char *const argv[])
>> } else
>> addr = image_load_addr;
>>
>> - if (!valid_elf_image(addr))
>> - return 1;
>> -
>> - if (sload && sload[1] == 'p')
>> - addr = load_elf_image_phdr(addr);
>> - else
>> - addr = load_elf_image_shdr(addr);
>> -
>> #if CONFIG_IS_ENABLED(CMD_ELF_FDT_SETUP)
>> if (fdt_addr) {
>> printf("## Setting up FDT at 0x%08lx ...\n", fdt_addr);
>> @@ -94,21 +74,26 @@ int do_bootelf(struct cmd_tbl *cmdtp, int flag,
>> int argc, char *const argv[])
>> }
>> #endif
>>
>> - if (!env_get_autostart())
>> - return rcode;
>> -
>> - printf("## Starting application at 0x%08lx ...\n", addr);
>> - flush();
>> + if (env_get_autostart()) {
>> + flags.autostart = 1;
>> + printf("## Starting application at 0x%08lx ...\n", addr);
>> + flush();
>> + }
>>
>> /*
>> * pass address parameter as argv[0] (aka command name),
>> * and all remaining args
>> */
>> - rc = do_bootelf_exec((void *)addr, argc, argv);
>> + rc = bootelf(addr, flags, argc, argv);
>> if (rc != 0)
>> rcode = 1;
>>
>> - printf("## Application terminated, rc = 0x%lx\n", rc);
>> + if (flags.autostart) {
>> + if (ENOEXEC == errno)
>> + printf("## Invalid ELF image\n");
>> + else
>> + printf("## Application terminated, rc = 0x%lx\n", rc);
>> + }
>>
>> return rcode;
>> }
>> diff --git a/include/elf.h b/include/elf.h
>> index a4ba74d8ab..b88e6cf403 100644
>> --- a/include/elf.h
>> +++ b/include/elf.h
>> @@ -12,6 +12,12 @@
>> #ifndef __ASSEMBLY__
>> #include "compiler.h"
>>
>> +/* Flag param bits for bootelf() function */
>> +typedef struct {
>> + unsigned phdr : 1; /* load via program (not section)
>> headers */
>> + unsigned autostart : 1; /* Start ELF after loading */
>> +} Bootelf_flags;
>> +
>> /* This version doesn't work for 64-bit ABIs - Erik */
>>
>> /* These typedefs need to be handled better */
>> @@ -700,6 +706,10 @@ unsigned long elf_hash(const unsigned char *name);
>> #define R_RISCV_RELATIVE 3
>>
>> #ifndef __ASSEMBLY__
>> +unsigned long bootelf_exec(ulong (*entry)(int, char * const[]),
>> + int argc, char *const argv[]);
>> +unsigned long bootelf(unsigned long addr, Bootelf_flags flags,
>> + int argc, char *const argv[]);
>> int valid_elf_image(unsigned long addr);
>> unsigned long load_elf64_image_phdr(unsigned long addr);
>> unsigned long load_elf64_image_shdr(unsigned long addr);
>> diff --git a/lib/elf.c b/lib/elf.c
>> index 9a794f9cba..0f3d752758 100644
>> --- a/lib/elf.c
>> +++ b/lib/elf.c
>> @@ -7,6 +7,7 @@
>> #include <cpu_func.h>
>> #include <elf.h>
>> #include <env.h>
>> +#include <errno.h>
>> #include <net.h>
>> #include <vxworks.h>
>> #ifdef CONFIG_X86
>> @@ -15,6 +16,41 @@
>> #include <linux/linkage.h>
>> #endif
>>
>> +/* Allow ports to override the default behavior */
>> +unsigned long bootelf_exec(ulong (*entry)(int, char * const[]),
>> + int argc, char *const argv[])
>> +{
>> + return entry(argc, argv);
>> +}
>> +
>> +/*
>> + * Boot ELF from memory
>> + *
>> + * addr - loading address of ELF in memory
>> + * flags - bits like ELF_PHDR to control boot details
>> + * argc, argv - may be used to pass command line arguments (maybe
>> unused)
>> + *
>> + * Sets errno = ENOEXEC if ELF image is not valid
>> + */
>> +unsigned long bootelf(unsigned long addr, Bootelf_flags flags,
>> + int argc, char *const argv[])
>
> Moving bootelf functionality is a good idea as we want to be able to
> build without command line interface.
>
> We should define the library functions without usage of argc and argv.
> The translation from argv[], argc to the library function parameters
> should happen in cmd/elf.c.
>
> Best regards
>
> Heinrich
>
In the library ported part, command line arguments are not analyzed,
only passed
to the running image.
This is necessary to pass the command line arguments to the running
applications,
which is required for backward compatibility. In other cases, you can
replace argc
and argv with null values.
Perhaps there is a better engineering solution for putting this in the
library and
maintaining compatibility?
Translated with DeepL.com (free version)
Best regards
Maxim
>> +{
>> + unsigned long entry_addr;
>> +
>> + if (!valid_elf_image(addr)) {
>> + errno = ENOEXEC;
>> + return 1;
>> + }
>> +
>> + entry_addr = flags.phdr ? load_elf_image_phdr(addr)
>> + : load_elf_image_shdr(addr);
>> +
>> + if (!flags.autostart)
>> + return 0;
>> +
>> + return bootelf_exec((void *)entry_addr, argc, argv);;
>> +}
>> +
>> /*
>> * A very simple ELF64 loader, assumes the image is valid, returns the
>> * entry point address.
>
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